This study investigates the changes in large-scale resting-state functional connectivity of the brain in Alzheimer's disease (AD) patients compared to non-demented controls using graph theory and magneto-encephalography (MEG). The researchers used a phase lag index (PLI), a measure insensitive to volume conduction, to assess synchronization between all pairs of MEG channels in the lower alpha and beta frequency bands. They found that AD patients showed a significant decrease in mean PLI in these bands, particularly in the lower alpha band. Graph analysis revealed that the clustering coefficient and path length were both decreased in the lower alpha band, indicating a more random network structure. Modeling results suggested that the changes were better explained by a 'Targeted Attack' model, where connections between highly connected nodes ('hubs') were preferentially affected, rather than a 'Random Failure' model. These findings support the concept of AD as a disconnection syndrome and highlight the importance of understanding the specific network changes in AD.This study investigates the changes in large-scale resting-state functional connectivity of the brain in Alzheimer's disease (AD) patients compared to non-demented controls using graph theory and magneto-encephalography (MEG). The researchers used a phase lag index (PLI), a measure insensitive to volume conduction, to assess synchronization between all pairs of MEG channels in the lower alpha and beta frequency bands. They found that AD patients showed a significant decrease in mean PLI in these bands, particularly in the lower alpha band. Graph analysis revealed that the clustering coefficient and path length were both decreased in the lower alpha band, indicating a more random network structure. Modeling results suggested that the changes were better explained by a 'Targeted Attack' model, where connections between highly connected nodes ('hubs') were preferentially affected, rather than a 'Random Failure' model. These findings support the concept of AD as a disconnection syndrome and highlight the importance of understanding the specific network changes in AD.